Multiple Hash key values problem !!

ashnator has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I have 2 files and I am taking the key values from one file and parsing in the other file for values. Now I am getting a problem of multiple values for the same key like this:-

File 1 Looks like this:-
DAVID 31
DAVID 29
DAVID 41

File 2 looks like this:-
>DAVID
40 40 40 40 40 40 40 40 40 33 40 40 40 40 40 40 40 40 40 40 40 40 40 4
+0 40 40 40 40 40 40 40 40 40 40 40 40
>DAVID
40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 66 40 40 6 40 40 40 40 40
+ 40 40 40 40 40 40 29 40 40 40 6 40
>DAVID
40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 4
+0 40 40 99 40 40 40 40 40 40 4 40 40
[download]

How can I deal with this since Perl Hash array supports only one value for a single key.
Actually I am doing it like this ,e.g,. If David value in File 1 is 31 then I search it in File 2 for 31 position and if 31 position in File 2 is >=20. Then my result looks like this:-

RESULT FILE:-
DAVID 31 40
DAVID 29 40  # This line is not printed bcoz hash can take only single
+ key
DAVID 41 40  # This line is not printed bcoz hash can take only single
+ key
[download]

Can you please suggest me how should I change my code to accommodate this short coming ?
Here is my sample code:-

#!/usr/bin/perl -w
use strict;

  my %href;

      my $fn = <STDIN>;

      open(FH, "$fn") || die "Cannot open file";



      while (<FH>) {

              chomp($_);

              $href{$1} = $2 if $_ =~ /(\S+)\s+(\S+)/;

      }



      while (my ($key, $value) = each(%href)) {

              #print $key. ", ". $value."\n";

      }

open(FD,"<FileToBeParsedForValues.txt") || die("Can't open: $!");

$/ = '>';

while ( <FD> ) {

    chomp;

    next unless ( s{ \A (\S+) \s+ (?= \d ) }{}xms and exists( $href{$1
+} ));


    my $name = $1;

    my @numbers = split /\D+/;

    my $one_number = $numbers[$href{$name} - 1];

    if ( $one_number >= 20 ) {

        print "$name\t\t$href{$name}\t$one_number\n";

    }

}
close FD;
[download]

Comment on Multiple Hash key values problem !! Select or Download Code

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Re: Howto deal with multiple Hash key values by gwadej (Chaplain) on Nov 06, 2008 at 01:52 UTC
The solution to this is actually quite simple. The values in a hash must be scalars. References are scalars. So use array references as the hash values. Replace `$href{$1} = $2 if $_ =~ /(\S+)\s+(\S+)/;` [download] with `push @{$href{$1}}, $2 if $_ =~ /(\S+)\s+(\S+)/;` [download] You'll need a little more work to use the value data, but you haven't lost any of it. `while (my ($key, $value) = each(%href)) { print "$key, (@{$value})\n"; }` [download] The rest of your code will need similar modifications to adapt to arrays of values. G. Wade	[reply] [d/l] [select]
Re: Howto deal with multiple Hash key values by repellent (Priest) on Nov 06, 2008 at 01:57 UTC
Please read Perl Data Structures Cookbook. `use warnings; use strict; my %hash; push @{ $hash{key1} }, 1, 2, 3; $hash{key2} = [ 4, 5, 6 ]; my $array_ref1 = $hash{key1}; print "$array_ref1->[2]\n"; # output: 3 my $array_ref2 = $hash{key2}; print "$array_ref2->[1]\n"; # output: 5` [download]	[reply] [d/l]
Re: Howto deal with multiple Hash key values by toolic (Bishop) on Nov 06, 2008 at 02:04 UTC
You could use HASHES OF ARRAYS: `use strict; use warnings; use Data::Dumper; my %hoa; while (<DATA>) { my ($name, $num) = split; push @{$hoa{$name}}, $num; } print Dumper(\%hoa); __DATA__ DAVID 31 DAVID 29 DAVID 41` [download] prints: `$VAR1 = { 'DAVID' => [ '31', '29', '41' ] };` [download]	[reply] [d/l] [select]